ITMC Instrumentation & Measurement 3

Question 1

What is hysteresis in a measuring instrument?

Accepted Answer

The difference in output for the same input depending on whether the input is increasing or decreasing

Answer

The maximum overload pressure an instrument can withstand without damage

Answer

The difference between an instrument's reading and the true value of the measured variable

Answer

The time constant describing how fast the instrument responds to input changes

Question 2

Which level measurement device operates on the principle of hydrostatic pressure from the liquid column above the sensor?

Accepted Answer

Differential pressure level transmitter

Answer

Float-and-tape level gauge

Answer

Ultrasonic level transmitter

Answer

Capacitance level probe

Question 3

In process control terminology, what does 'PV' stand for?

Accepted Answer

Process Variable

Answer

Process Voltage

Answer

Primary Value

Answer

Pressure Volume

Question 4

What is the purpose of a flow totalizer in an instrumentation system?

Accepted Answer

To accumulate and display the total volume of fluid that has passed a measurement point over time

Answer

To limit the maximum flow rate allowed through a metered pipe section

Answer

To calculate and report the average flow rate over a defined time period

Answer

To compare instantaneous flow against a setpoint and trigger an alarm on deviation

Question 5

Which type of pressure measurement references the process pressure against local atmospheric pressure?

Accepted Answer

Gauge pressure

Answer

Absolute pressure

Answer

Differential pressure

Answer

Compound pressure

Question 6

What does a PID controller calculate to generate its output signal?

Accepted Answer

A corrective output based on Proportional, Integral, and Derivative error terms to minimize setpoint deviation

Answer

The average process variable value over the last sampling interval

Answer

The raw sensor signal converted to engineering units for the operator display

Answer

The difference between two redundant sensor readings to detect instrument failure

Question 7

What is the primary advantage of a smart (HART-enabled) transmitter over a conventional analog transmitter?

Accepted Answer

It superimposes digital communication on the 4-20 mA signal for remote configuration and diagnostics

Answer

It operates without requiring any external power supply

Answer

It produces a higher output current range for better noise immunity

Answer

It eliminates the need for calibration because it self-corrects automatically